LONDON, June 30 (UPI) -- Researchers have identified a specific genetic change that prevents the body from producing a protein important for processing a number of hormones and brain transmitters controlling appetite, insulin and other hormones important in the reproductive system.
While scientists are unsure of the proportion of people whose obesity or diabetes is caused by inherited genetic changes, there are more than 30 genes that can create risk factors for the conditions.
"There are now an increasing number of single-gene causes of obesity and diabetes known," Professor Alex Blakemore, of the Department of Medicine at Imperial College London, said in a press release. "We don't know how many more have yet to be discovered, or what proportion of the severely obese people in our population have these diseases -- it is not possible to tell just by looking.
Researchers sequenced the DNA of a morbidly obese 20-year-old woman and six members of her family who, in addition to childhood onset obesity, had an increased appetite, type 2 diabetes, learning difficulties and reproductive problems.
The woman was found to have two copies of a harmful genetic alteration, which prevents her body from making carboxypeptidase-E, or CPE, which helps to control appetite, insulin and other hormones related to the reproductive system. CPE deficiency is a recessive, inherited trait, meaning that both of her parents carried the gene, as well.
"These are serious disorders that affect the body's ability to regulate hunger and fullness signals," Blakemore said. "They are inherited in the just same way as other genetic diseases and the sufferers should not be stigmatized for their condition. They should be offered genetic counseling and specialized lifelong support to allow them as healthy a life as possible."
The study is published in PLOS ONE.